Digging tooth for excavators



July 3, 1956 w. A. NELSON 2,752,702

DIGGING TOOTH FOR EXCAVATORS Filed Aug. 6, 1952 2 Sheets-Sheet l rrg- 1 frg- 4 INVENTOR. W AN A. NELJOA/ July 3, 1956 w, NELSON 2,752,702

DIGGING TOOTH FOR EXCAVATORS Filed Aug. 6. 1952 2 Sheets-Sheet 2 llllllflllgll lllllj INVENTOR. W/u 14!? A. M150 BY 2,752,702 DIGGING TODTH FOR EXCAVATORS 2 Claims. (Cl. 37-142) assignor to The Cleveland, Ohio, a cor- This invention relates to digging or rooter teeth for use with the digging buckets of rotary excavator wheels, or excavating chains of trenching machines, and the like. More particularly, the present invention relates to improved excavator teeth having removable cutting or rooter members at their digging edges.

The digging or rooter teeth or excavating machine buckets are subjected to severe shock, usage and/or wear, particularly when the machine is operated in stony soil or in areas where heavy roots are encountered. In the past teeth have been provided which comprised a base adapted to be fastened to the excavating buckets by welding, bolts, rivets, or the like, and which carried removable tips. This has facilitated reforging the tip to restore it to its original shape; rehardening of the wearing surface of the tip; or forging operations; or replacement by a new tip. Diverse constructions have been used to mount the tips on their bases. Generally such constructions included means such as bolts, keys or the like. The impacts to which the teeth are subjected during excavating operations soon distort such bolts etc., and prevent removal of the tips for replacement or sharpening.

Another method of mounting the tip on the base is shown in Patent No. 2,397,521 issued to my assignee, The Cleveland Trencher Company, discloses a base and tip having telescoping portions, substantially rectangular in cross section and provided with tapered walls, and wherein such portions are formed to insure contact between the corners of the internal member with the walls of the coacting socket, prior to engage ment between the other surface of such coacting portions. Such rooter teeth have been successfully used for some time. However in the last few years a considerable advance has been made in the resulted in the production of a higher grade of metals, especially with relation to their properties on the one hand and manufacture and treatment on the other. Such advance has permitted the provision of rooter teeth which are much harder and capable of use for a much longer period of time than the teeth formerly used. However these advances have increased the difliculty in attaching the removable tip to the rooter shank to insure a secure attachment and yet facilitate the removal of the tip when desired.

A more specific object of the present invention is to provide a rooter base and removable tip therefor which are so and tip, and thereby prolong the life of the base and tip.

The various objects and features of this invention will be more fully understood from the following detailed description of a typical form of the invention illustrated in the accompanying drawings, in which:

Fig. 1 is a fragmentary view of a portion of an excavating wheel illustrating an excavating bucket provided with the improved excavating teeth;

to improvements in or relating building up of the tip by welding April 2, 1946. This patent ice Fig. 2 is a plan view of the improved excavating tooth showing the tip in place on the tooth base;

Fig. 3 is a view similar to Fig. 2, but illustrating the tip separated from the base;

Fig. 4 is a central longitudinal section through the base and separated tip, the plane of the section being indicated by the lines 4-4 on Fig. 3;

Fig. 5 is a fragmentary longitudinal section similar to Fig. 4 but illustrating the start of the assembly of the base and tip;

Fig. 6 is a fragmentary central longitudinal section 'milar to Fig. 4 illustrating the base and tip completely assembled, the plane of the section being indicated by the lines 66 on Fig. 2;

Fig. 7 is a fragmentary section similar to Fig. 6 but taken in the plane indicated by the lines 7-7 on Fig. 3;

Fig. 8 is a fragmentary longitudinal section the plane of which is indicated by the lines 8-8 on Fig. 6;

Fig. 9 is a transverse section through the tooth base as indicated by the lines 9-9 on Fig. 3;

Fig. 10 is a transverse section through the tooth tip as indicated by the lines 101t) on Fig. 3; and

Fig. 11 is a transverse section through the assembled base and tip, the plane of which is indicated by the lines il-1l on Fig. 2.

Referring now to the drawings, particularly to Fig. l, 15 indicates a portion of an excavating wheel provided with excavating buckets, one of which is indicated at 16.

The machine itself may be of the type shown in Patent No.

Fig. l, of the excavating buckets will engage the material to be excavated.

The improved rooter or digger teeth 19 are shown as being applied to the bucket 16 by bolts or rivets 17 which pass through openings 13 in the tooth base 20, and through the wall of the bucket. place on the teeth 19.

on the shank solely by frictional engagement between the walls of the shank and socket. As illustrated in the drawings and particularly in Figs. 4 and 8 the walls 24, of the shank 21, and the walls 34 of the socket 31, are

upper and lower surfaces of the shank, as shown in Figs. 9 and 11, while the side walls of the socket are substantially arcuate. The radius of the arcs of the side walls is such as to prevent binding contact between the central and major portions of the enacting side walls and socket at all times. The width of the shank and socket are so related as to insure contact between all four corners of the shank and the walls of the socket prior to engagement of the top and bottom surfaces thereof. Thus the tip is held firmly against rocking movements on the shank. Further, this initial contact at the corners has another distinct advantage, namely, a small space or low pressure area exists between the faces of the shank and the faces of the walls of the socket, thus permitting swelling of the shank due to compression thereof caused by impact during the digging operation. The spaces between the central portion of the top and bottom walls of the shank are increased by undercut areas 26 of the shank, caused by repeated impacts during the digging operations. reacts against the weaker or wider face of the tip, which, due to its width, may warp slightly to accommodate this swelling action.

With the exception of the undercut portions 26, the tooth so far described is substantially that of Patent 2,397,521, heretofore mentioned. Accordingly reference may be had to that patent for a more complete description of the details of such tooth base and shank, together with the manner in which they cooperate one with the other. Such a construction facilitates the use of detachable tips when the shank and tips are made of many types of metal alloys.

As heretofore mentioned, considerable difliculty has been encountered in maintaining the tip in position on the shank when using the higher grade metal alloys being produced at the present time and or improved hardening treatment for manufacture of the tip. particularly when the excavating wheel is inadvertently operated in reverse direction. To overcome these disadvantages and permit the use of the higher grade metal alloys thereby lengthening the life of the tip, the present invention provides additional means to retain the tip in place on the shank and yet permit it to be readily removed for purposes heretofore described.

Referring to the drawing it will be seen that the upper surface 49 of the shank 21 is provided with a raised boss or protuberance in the form of :a button 41, this protuberance or button has conical side walls 42 and its upper surface extends about one sixty-fourth of an inch above the upper surface of the corners of the shank. The boss 41 is positioned near the end of the shank and intermediate its side walls. The upper surface of the boss is made parallel with the upper surface of the shank 21.

The heighth of the boss 41 is such that in assembly it will enter the tip socket 31 as shown in Fig. and seat firmly in that position. After the ti-p has been positioned as shown in Fig. 5, it is fully seated by applying a driving impact to the end 44 of the tip, until it reaches substan- The swelling action of the shank 9 4 tially the position of Fig. 6. In this position the engagement of the tapered walls of the shank 21 with the tapered walls of the tip socket by corner engagement, as heretofore described, prevents further movement of the tip onto the shank.

The increased holding power of the tooth of this invention comes as a result of an actual deformation of the upper fiat wall 45 of the tip which is realized by the driving force applied when the tips are hammered onto the bases. This distortion also causes the binding action between the corner of the tip and in the corner of the shank to be increased. However, despite the increased holding power it has been found that the tip may be removed by hammering against the rear surfaces 46 of the tip. It has likewise been found that despite the deformation of the wall 45, the tip may be reapplied to the shank several times without materially afiecting the holding power.

I claim:

1. A digging tooth for an excavator, said tooth comprising a metallic base member and a metallic tip member, said base being adapted to be attached to an excavator member and having a shank substantially rectangular in cross section throughout its length, at least one of the walls of the shank being tapered, a tooth tip adapted to be removably positioned on sa'd shank, said tip having a socket substantially complementary in cross section that of the shank and having at least one of its walls being tapered, the tapered wall of said socket being planar, the tapered wall of said shank having an outward extending protuberance, of the shank intermediate its sides and adapted to freely enter the socket when the tip is initially positioned on the shank and to thereafter distort the wall :of the tip as the tip is driven onto the shank :and to retain such wail distorted as long :as the tip is in position on the shank, and wherein when the tip is in position on the shank said protuberance exerts a constant outward deforming pres-- sure on the enacting Wall of the tip thereby drawing the associated corners of the tip into tighter engagement with the coasting corners of the shank respectively.

v2. A digging tooth accorc'lin-g to claim 1 wherein said protuberance comprises a button shaped member arising above the wall :of the shank and is spaced inward from the associated side walls of the shank and inward from the end of the shank.

References Cited in the tile of this patent said pnotuberance rising above the Wall. 

